dleigh@hplabsz.HPL.HP.COM (Darren Leigh) (05/03/89)
Well, my power supply just gave up the ghost. It's especially annoying because the problem began while my machine was still under warranty, but I just thought that amigas crashed a lot. At first my 2000 would crash randomly with guru numbers 3 and 4. It was suggested to me that either I had a memory problem or that my power supply was bad. I took the 2 Meg card out and the crashing stopped so I assumed it was at fault, though I was not able to spot any bad bits with memory diagnostics. Everything was OK for a while, then the power supply started acting funny. Sometimes when I turn it on it dies immediately. Sometimes it stays on for 30 seconds to a minute before dying. Once it's on, it tends to stay on. Today I haven't been able to get it to work at all so I pulled it out and began looking at it with more advanced equipment. Here's a description of what happens: I turn it on, the fan starts up and the +5 rail turns on nicely, then the fan shuts off and I only get a volt or so out of the +5 supply. I guess the power supply is getting crowbarred? The power supply claims to be made in Hong Kong by Elec & Eltek Power Supply LTD. It is model number 420504-SD and has a date code of 8815. There are two white stickers on it, one saying REV. 00 and the other saying PASSED HI-POT. Are there any known problems with this supply? Known fixes? From the feedback I got before, I gather that mine is not an isolated problem. I really wish that Commodore products had a one year warranty. It would go a long way toward proving to businesses that the Amiga is a realiable machine. (Is it really reliable? As much as I love the machine, both of my amigas were incredibly flakey. And considering how many monitors have been burning up lately . . .) Until I can find a real replacement supply, I'll hack something together from parts at hand. I know what voltages are on most of the connectors, but does anyone have a pinout for the long 14 pin socket? I guess I only need to know what's on the red, green, white and brown lines. I called various dealers here in the Bay Area and was told that replacement supplies are $150. No one seems to have them in stock either (though they always say they do until you ask them to check). One hundred fifty seems steep -- where can I get one (or a similar one that will fit in the case) cheaper? In a similar vein, where in the SF bay area (southern penninsula preferred) can I get fast and competent repair service? I'm really disgusted by the repair people I've been talking to who either don't know what they're doing or tell me lies. ======== Darren Leigh Internet: dleigh@hplabs.hp.com UUCP: hplabs!dleigh
wtm@neoucom.UUCP (Bill Mayhew) (05/03/89)
Many switch-mode power supplies will not run correctly unless a proper load it attached. If you take the power supply out of the machine for bench examination it is likely that the operation will be erratic. If the 5 volts is coming on, then clamping down to about a volt after a few seconds *with the mother board attached*, it sounds like the over-voltage crowbar protection is shutting down the power supply. How close is the 5 volt output to 5.00 volts? Check it with a decent digital meter. Don't use a $5.95 ArcherKit piece of junk to measure it. If the voltage is too high, adjust the the voltage pot carefully (if you can locate it). I don't have a B2000, but I'd be willing to bet there is a 5 volt adjustment pot lurking in there somewhere in the power supply. If you don't know what you're doing, by all means take it to a decent repair center and let them fix it. Remember if you poke around in the power supply, you might be electrocuted. Don't take chances. Bill wtm@impulse.UUCP
bryan@cs.utexas.edu (Bryan Bayerdorffer @ Wit's End) (05/04/89)
In article <3285@hplabsz.HPL.HP.COM> dleigh@hplabs.UUCP (Darren Leigh) writes: =-Well, my power supply just gave up the ghost. It's especially =-Here's a description of what happens: I turn it on, the fan starts up =-and the +5 rail turns on nicely, then the fan shuts off and I only get =-a volt or so out of the +5 supply. I guess the power supply is =-getting crowbarred? =- =-The power supply claims to be made in Hong Kong by Elec & Eltek Power =-Supply LTD. It is model number 420504-SD and has a date code of 8815. Yep, that's the very problem I had with the very same power supply about six months ago, only mine was older (1/87). The fan had started to sound like its bearings were going to seize any minute, despite repeated meticulous cleanings of the blades. So, I tore it out of the cage and fiddled with it---flipped and lubed the bearings, etc. When I plugged it back in and reassembled everything it ran ok---for about 15 seconds after reboot. Uh oh, power failure, thought I. But no, the desk lamp is still on. Hmm. Try to cycle the power. It gets about 10 seconds into the reboot, and then, bereft of life it rests in peace. From then on all I get is the crowbar effect. It was natural for me to assume that I'd done something unspeakable whilst messing with the fan and its immediate surroundings, but it turned out that the big radial cap that sits next to the terminal into which the fan wires are plugged (northwest corner of the board) had chosen that moment to spring a leak bad enough to cause the supply to crowbar itself down. Upon replacing that capacitor, all was well. I took the opportunity to swap the Hong Kong Turbine for a Radio Shack 12VDC fan, which sounds significantly less like the business end of a 727. ______________________________________________________________________________ /_____/_____/_____/_____/_____/_____/_____/_____/_____/_____/_____/_____/_____/ |_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____| _No dark sarcasm in the classroom|_____|_____|_____|_____|_____|_____|_____|___ |____Teachers leave the kids alone__|_____|_____|_____|_bryan@cs.utexas.edu___| ___|_____|_____|_____|_____|_____|_____|{vertebrae...}!cs.utexas.edu!bryan_|___ |_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|_____|
davidc@ziebmef.uucp (David Carlton) (05/11/89)
In article <3285@hplabsz.HPL.HP.COM>, dleigh@hplabsz.HPL.HP.COM (Darren Leigh) writes: > > I really wish that Commodore products had a one year warranty. It > would go a long way toward proving to businesses that the Amiga is a > realiable machine. (Is it really reliable? As much as I love the > machine, both of my amigas were incredibly flakey. And considering > how many monitors have been burning up lately . . .) Strange... Here in Canada all Commodore products have a one year warranty. They started this early last year, to the surprise of all. It's the best thing that has happened in a while! NOTE: The warranty does of course not apply to the C64 or 128 series and any equipment relating to them. (Thank god! 'Cause I fix them!) 8} *Take me! Just leave my employers/friends and family out of it! -- David Carlton ..!{uunet!atcan!telly!magsta,utgpu,ontmoh,ziebmef}!davidc